Researchers Explore How Diseases Travel in the Brain

A new study of synapses—the areas of the brain where cells connect—has revealed information about how diseases like Alzheimer’s spread. Work by Patrik Verstreken, PhD, of the Flanders Institute for Biotechnology, in collaboration with Janssen Research and Development, has centered on the important role that synapses play in the progress of neurodegenerative diseases, which are affecting more Americans as the baby boomer population ages and people live longer.

When Alzheimer’s disease occurs, toxic proteins spread throughout the brain, affecting more and more parts of the brain over time as the disease progresses. “You can compare it to a drop of ink that falls into a glass of water: gradually, the toxic proteins diffuse through the brain,” Verstreken said in a press release. “We knew that the disease follows the existing brain paths, but so far it wasn’t clear which processes enabled the spread itself.”

In their experiment, the researchers found mechanisms known as vesicles, which are small bubbles that burst and release the toxic proteins in the brain cell. The vesicles facilitate the proteins’ travel from cell to cell.

“We also show how familial history has an impact in this process,” Verstreken said. “There are known genetic factors in the human population that increase the risk to develop Alzheimer’s and we show that one of the more common genetic variants, dubbed BIN1, directly affects the transmission of toxic proteins at synapses. BIN1 improves the transmission at synapses, but in doing so, it enables the spread of the toxic protein.”

Tracing these paths can open the door for treatment of neurodegenerative diseases. Researchers could devise a way to block the process by which the proteins are passed along the synapses, or reroute the toxins in a way that would make them less harmful.

Alzheimer’s disease alone costs the United States $236 billion a year, which is on par with diabetes, even though the disease affects only a sixth of that population at 5 million. It threatens to drown Medicare if better treatments are not found.